#ifdef GL_ES
precision mediump float;
#endif
uniform vec2 resolution;
void drawBg();
void drawGradBg();
void drawSimpleCircle();
void main(){
    // drawGradBg();
    drawSimpleCircle();
}

void drawBg(){
    vec3 color=vec3(0.1098, 0.698, 0.2941);
    gl_FragColor=vec4(color,1);
}

void drawGradBg(){
    vec2 point=gl_FragCoord.xy/resolution;
    gl_FragColor=vec4(point.x,0,0,0.5);
}

void drawSimpleCircle(){ 
    vec2 pt=gl_FragCoord.xy/resolution-0.5;
    float lengthV=length(pt);
    float stepV=1.0-step(0.5,lengthV);
    gl_FragColor=vec4(stepV,stepV,stepV,1.0);
}